C# convert int to string with padding zeros?

问题

In C# I have an integer value which need to be convereted to string but it needs to add zeros before:

For Example:

int i = 1;

When I convert it to string it needs to become 0001

I need to know the syntax in C#.

回答1:

i.ToString().PadLeft(4, '0') - okay, but doesn't work for negative numbers
i.ToString("0000"); - explicit form
i.ToString("D4"); - short form format specifier

回答2:

i.ToString("D4");

See MSDN on format specifiers.

回答3:

Here's a good example:

int number = 1;
//D4 = pad with 0000
string outputValue = String.Format("{0:D4}", number);
Console.WriteLine(outputValue);//Prints 0001
//OR
outputValue = number.ToString().PadLeft(4, '0');
Console.WriteLine(outputValue);//Prints 0001 as well

回答4:

You can use:

int x = 1;
x.ToString("0000");

回答5:

C# 6.0 style string interpolation

int i = 1;
var str1 = $"{i:D4}";
var str2 = $"{i:0000}";

回答6:

i.ToString("0000");

回答7:

Easy peasy

int i = 1;
i.ToString("0###")

回答8:

Simply

int i=123;
string paddedI = i.ToString("D4");

回答9:

.NET has an easy function to do that in the String class. Just use:

.ToString().PadLeft(4, '0')  // that will fill your number with 0 on the left, up to 4 length

int i = 1; 
i.toString().PadLeft(4,'0')  // will return "0001"

回答10:

int p = 3; // fixed length padding
int n = 55; // number to test

string t = n.ToString("D" + p); // magic     

Console.WriteLine("Hello, world! >> {0}", t);

// outputs: 
// Hello, world! >> 055

回答11:

Here I want to pad my number with 4 digit. For instance, if it is 1 then it should show as 0001, if it 11 it should show as 0011.

Below is the code that accomplishes this:

reciptno=1; // Pass only integer.

string formatted = string.Format("{0:0000}", reciptno);

TxtRecNo.Text = formatted; // Output=0001

I implemented this code to generate money receipt number for a PDF file.

回答12:

To pad int i to match the string length of int x, when both can be negative:

i.ToString().PadLeft((int)Math.Log10(Math.Abs(x < 0 ? x * 10 : x)) + 1, '0')

来源：https://stackoverflow.com/questions/4325267/c-sharp-convert-int-to-string-with-padding-zeros

标签

formatting

number-formatting